Strumigenys formosa ( Terayama et al., 1995 )

Tang, Kit Lam & Guénard, Benoit, 2023, Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species, European Journal of Taxonomy 907, pp. 1-144 : 60-62

Strumigenys formosa ( Terayama et al., 1995)

Fig. 20 ; Table 2

Epitritus formosus Terayama et al., 1995: 85 , figs 1–4 (q.) TAIWAN. Indomalaya.

Pyramica formosa – Bolton 1999: 1672.

Strumigenys formosa – Baroni Urbani & De Andrade 2007: 120.

Material examined

MAINLAND CHINA – Hainan Province • 1 worker; Yinggeling, YGLK5; 19.075584° N, 109.524615° E; 31 Jul. 2016; L. Wang leg.; Winkler, 4 corners; IBBL • 1 worker; Yinggeling, YGLK9; 19.092689° N, 109.534550° E; 1 Aug. 2016; L. Wang leg.; Winkler, 4 corners; IBBL .

HONG KONG • 1 alate queen; Kwai Tsing District , Tsing Yi Park; 22.35768° N, 114.1045° E; 27 m a.s.l.; 9–16 Aug. 2021; A. Ibanez leg.; Malaise trap; urban park; IBBL .

THAILAND – Trang Province • 1 worker; Khao Chong, Site 12-1 (KCW12-1); 7.5436° N, 99.8067° E; 27 Dec. 2018; IBBL members legs.; Winkler, 4 corners; primary forest; IBBL ANTWEB1011958 .

Measurements

Workers

TL 1.4–1.5, HL 0.31–0.34, HW 0.35–0.37, MandL 0.11–0.12, SL 0.17–0.20, EL 0.014 –0.016, PW 0.21– 0.24, ML 0.35–0.40, PL 0.17–0.18, PH 0.10–0.11, DPW 0.10–0.12, PPL 0.09–0.11, GL 0.34–0.39, CI 108–113, MI 36–37, SI 50–56, OI 4, LPI 58–60, DPI 58–63 (n=3).

Queen

TL 1.8, HL 0.37, HW 0.39, MandL 0.13, SL 0.24, EL 0.060, PW 0.26, ML 0.47, PL 0.19, PH 0.10, DPW 0.13, PPL 0.09, GL 0.52, CI 108, MI 35, SI 61, OI 15, LPI 54, DPI 68 (n=1).

Geographic range

Mainland China (Hainan, Hong Kong, Yunnan), Taiwan, Thailand (Trang).

New record for Hainan, Yunnan and Thailand.

Ecology

Workers collected in rubber and agro-rubber plantations in Hainan, and primary forest in Thailand. Queen collected in urban park in Hong Kong.

Comments

The species was initially described from two queens from Taiwan in 1988, until one single worker was collected in Hong Kong and re-described in Tang et al. (2019). Here, we present a recently collected queen using a Malaise trap at Tsing Yi, Hong Kong, that can be identified as S. formosa ( Fig. 20A–C ), which supports the record of the species from Hong Kong. The specimens from Hainan ( Fig. 20D–F ) and Thailand ( Fig. 20G–I ) match the description of the worker from Hong Kong, with simple setae instead of spatulatiform ones overhanging the inner margin of the mandible in full-face view.

The species is very similar to S. dyschima , except for the aforementioned character, and as its worker diagnosis was not available until 2019, it is prone to misidentification. Specimens from Yunnan that were reported previously by Liu et al. (2015) show simple setae in the inner margin of the mandible, which indicates it is S. formosa misidentified as S. dyschima .

This species was considered, for some time, endemic to Taiwan. With the recent records from Hong Kong, and here reported from southern Thailand and Hainan and Yunnan provinces of mainland China, it is in fact more widely distributed within Southeast Asia. Future records of this species in Guangdong and Guangxi provinces of mainland China, as well as Laos and Vietnam seem likely, while the recent record of this species from the northeast part of Sichuan Province ( Luo & Zhou 2022) needs verification.

Figures

Fig. 20. Specimens of Strumigenys formosa (Terayama et al., 1995) in full-face, profile and dorsal views. A–C. Alate queen from Hong Kong (TYIMI-11). D–F. Worker from Hainan, mainland China (HNA-00044). G–I. Worker from Thailand (ANTWEB1011958).